It is well known in motor vehicles to restrain the occupant's head via a head rest. Such a head rest may be integral with the vehicle seat, or the head rest may be suitably mounted on the vehicle roof structure.
It is also known to restrain the occupant by a restraining seat belt which may include a lap belt and a shoulder belt. The shoulder belt conventionally has an upper end mounted on one side of the occupant torso and the lower end suitably mounted on the vehicle body or the seat at the other side of the occupant torso so that the shoulder belt is deployed diagonally across the upper torso of the seat occupant. In the prior art the upper end of the shoulder belt has been proposed for mounting either on the roof, the door pillar, or on the seat itself. The disadvantage of mounting the upper shoulder belt on the seat is that the seat back must be strengthened to withstand the occupant restraint load imposed thereon.
It has been recognized in the prior art that the head rest should be adjustable fore and aft and/or up and down in response to adjusting movement of the seat so that the head rest is optimally positioned with respect to the occupant.